Robert D. Drennan was Distinguished Professor Emeritus at the University of Pittsburgh, where he founded the Center for Comparative Archaeology. A member of the National Academy of Sciences, he had conducted field research in Mesoamerica, Colombia, and China. Christian E. Peterson is Professor of Anthropology at the University of Hawai'i at Mānoa. He specializes in the comparative study of early complex societies, regional settlement analysis, household archaeology, and in quantitative methods. His archaeological field research focuses on the emergence of social complexity in Northeastern China and South Africa. C. Adam Berrey is an anthropological archaeologist specializing in the comparative study of early complex societies. He received his PhD in Anthropology from the University of Pittsburgh and is Assistant Professor of Anthropology at California State University, Sacramento. He conducts field research in central and eastern Panama.

'As only archaeology can document, Emergence of Social Complexity is foundational to an historical science of human societies. The authors creatively analyze rich archaeological evidence from many 'natural experiments'. They show how to rank key variables, such as monumentality, wealth, and population, to understand developmental interactions as 'rhymes in time.'' Timothy Keese Earle, Northwestern University

• 1. Early social complexity: restructuring social roles and relationships; 2. Archaeological comparison: challenges, quantification, and robust analysis; 3. Variation characterized and explored; 4. Finding rhymes; 5. Complexification trajectories that rhyme; 6. What bundles of trajectories reveal about complexification; 7. Focusing future research; Appendix. Supporting data online; References cited.

Robert D. Drennan was Distinguished Professor Emeritus at the University of Pittsburgh, where he founded the Center for Comparative Archaeology. A member of the National Academy of Sciences, he had conducted field research in Mesoamerica, Colombia, and China. Christian E. Peterson is Professor of Anthropology at the University of Hawai'i at Mānoa. He specializes in the comparative study of early complex societies, regional settlement analysis, household archaeology, and in quantitative methods. His archaeological field research focuses on the emergence of social complexity in Northeastern China and South Africa. C. Adam Berrey is an anthropological archaeologist specializing in the comparative study of early complex societies. He received his PhD in Anthropology from the University of Pittsburgh and is Assistant Professor of Anthropology at California State University, Sacramento. He conducts field research in central and eastern Panama.

'As only archaeology can document, Emergence of Social Complexity is foundational to an historical science of human societies. The authors creatively analyze rich archaeological evidence from many 'natural experiments'. They show how to rank key variables, such as monumentality, wealth, and population, to understand developmental interactions as 'rhymes in time.'' Timothy Keese Earle, Northwestern University

• 1. Early social complexity: restructuring social roles and relationships; 2. Archaeological comparison: challenges, quantification, and robust analysis; 3. Variation characterized and explored; 4. Finding rhymes; 5. Complexification trajectories that rhyme; 6. What bundles of trajectories reveal about complexification; 7. Focusing future research; Appendix. Supporting data online; References cited.

Robert D. Drennan was Distinguished Professor Emeritus at the University of Pittsburgh, where he founded the Center for Comparative Archaeology. A member of the National Academy of Sciences, he had conducted field research in Mesoamerica, Colombia, and China. Christian E. Peterson is Professor of Anthropology at the University of Hawai'i at Mānoa. He specializes in the comparative study of early complex societies, regional settlement analysis, household archaeology, and in quantitative methods. His archaeological field research focuses on the emergence of social complexity in Northeastern China and South Africa. C. Adam Berrey is an anthropological archaeologist specializing in the comparative study of early complex societies. He received his PhD in Anthropology from the University of Pittsburgh and is Assistant Professor of Anthropology at California State University, Sacramento. He conducts field research in central and eastern Panama.

'As only archaeology can document, Emergence of Social Complexity is foundational to an historical science of human societies. The authors creatively analyze rich archaeological evidence from many 'natural experiments'. They show how to rank key variables, such as monumentality, wealth, and population, to understand developmental interactions as 'rhymes in time.'' Timothy Keese Earle, Northwestern University

• 1. Early social complexity: restructuring social roles and relationships; 2. Archaeological comparison: challenges, quantification, and robust analysis; 3. Variation characterized and explored; 4. Finding rhymes; 5. Complexification trajectories that rhyme; 6. What bundles of trajectories reveal about complexification; 7. Focusing future research; Appendix. Supporting data online; References cited.